Structure and redox properties of CexSn1-xO2 mixed oxides

A variety of CexSn1-xO2 mixed oxides has been synthesized and their structu re and redox properties have been studied. The structure of CexSn1-xO2 mixe d oxides depends on values of 'x' and calcination temperature. When x=1.0 s imilar to0.8, CexSn1-xO2 mixed oxides an in cubic phase; on decreasing x fr om 0.7 to 0.1, CexSn1-xO2 mixed oxides are observed Co have cubic and tetra gonal mixed phases; and single SnO2 is in a tetragonal phase. Only small am ounts of SnO2 can be introduced into the CeO2 lattice to form cubic phase, and excess SnO2 is in tetragonal phase. Low calcination temperatures favour formation of Ce0.7Sn0.3O2 solid solutions, while high calcination temperat ures do not favour formation of solid solutions and lead to sample sinters. Combined with DTA result, we believe the Ce0.7Sn0.3O2 mixed oxides are for med during the decomposition of the dried sample at about 300 degreesC. The mixed oxides have three reduction peaks (alpha, beta and gamma). The peak alpha is attributed to the reduction of the easily reducible surface Sn4+. The peak beta is attributed to the overlapping peak of the reduction of bul k oxygen of SnO2 and the easily reducible surface Ce4+. The peak gamma is a scribed to the reduction of bulk CeO2. The intensity and temperature of red uction peaks are affected by x values and calcination temperatures.